Evaluation of Lethal Activity of Psidium Guajava Linn. Extracts on Bacterial Pathogens Causing Diarrheal Infections

Abstract

Treatment of diarrheal infections is often challenged by development of drug resistance among the bacteria. The aim of this study was to investigate the antibacterial property of extracts of guava (Psidium guajava Linn.) leaves against diarrhea causing bacterial pathogens. Four extracts viz., ethanol, methanol, ethyl acetate and hot water extract of guava leaf were assayed for antibacterial activity against three selected bacterial pathogens along with four commercial antibiotics. The methanol extract exhibited substantial inhibitory activity (100 %) against both kinds of bacteria with a MIC of > 250 µg/ml in most cases. The ethanol extract demonstrated antibacterial activity ranging from 38 % to 65 % with the inhibition of clinical isolate of E. coli at concentrations > 500 µg/ml and both strains of V. cholerae at > 750 µg/ml respectively. The ethyl acetate and hot water extracts showed comparatively lesser response with MICs > 750 µg/ml in some cases. The commercial antibiotic Chloramphenicol exhibited absolute inhibitory action on Salmonella sp. and clinical isolate of V. cholerae. While Tetracycline and Gentamycin caused complete bactericidal action on both the strains of E. coli and V. cholerae respectively, the clinical isolate of E. coli was totally susceptible to Erythromycin. On the other hand significant percentages of resistances to these antibiotics ranging from 63 % to 88 % were also recorded. Six phytochemical compounds presumed to possess pharmacological properties were detected from methanol extract. The findings suggest that the methanol extract of guava leaf could serve as a potential source to explore promising drugs to control diarrheal infections.

Health Effects of Psidium guajava L. Leaves: An Overview of the Last Decade

“…Moreover, other studies also demonstrated the antimicrobial effect of some bacteria that cause gastrointestinal disorders by different methods [ 34 , 35 ]. In contrast to previous results [ 20 , 31 ], no inhibition of the hydrodistillation and n-hexane extract was found against E. coli Salmonella spp. [ 31 ] ( Table 1 ).…”

“…In contrast to previous results [ 20 , 31 ], no inhibition of the hydrodistillation and n-hexane extract was found against E. coli Salmonella spp. [ 31 ] ( Table 1 ).…”

“…and Salmonella spp. [ 30 , 31 , 32 ]. It is suppose that the same plant origin and similar extraction procedure makes that these works show comparable inhibition zones for the bacteria tested [ 30 , 31 ], in contrast to the leaves of India and Bangladesh, where MIC values did not show any concordance [ 31 , 32 ] ( Table 1 ).…”

“…[ 30 , 31 , 32 ]. It is suppose that the same plant origin and similar extraction procedure makes that these works show comparable inhibition zones for the bacteria tested [ 30 , 31 ], in contrast to the leaves of India and Bangladesh, where MIC values did not show any concordance [ 31 , 32 ] ( Table 1 ). In addition, a reduction was described for S. flexneri and V. cholera invasion and for their adherence to the human laryngeal epithelial cells, and for the production of E. coli heat labile toxin and cholera toxin, as well as their binding to ganglioside monosialic acid enzyme [ 33 ].…”

Development and Validation of Uv Spectroscopy for the Estimation of Rutin From Ethanolic Extract of Cocculus Hirsutus Leaves

“…Chemically it is 5, 7, 3, 4, tetrahydroxy flavonol -3-rhamanoglucoside ( Figure 1) and widely used in medicine for maintenance of capillary integrity. It possesses anti-inflammatory, antihepatotoxic 2 , antiulcer 3 , antiallergic and antiviral actions and some of them provide protection against cardiovascular mortality [4][5][6] . It also has antioxidant activity and reduces low density lipoproteins [LDL] oxidation 7 .…”